1. Field of the Invention
This invention relates to a process for preparing a ruthenium-promoted, nickel and/or cobalt catalyst, and to a catalyst prepared by the process. Such catalysts are useful as dehydrogenation-hydrogenation catalysts and are particularly useful for the amination of alkylene oxides, hydroxyl-containing compounds, such as alcohols, phenols and alkanolamines, aldehydes and ketones.
2. Background of the Art
Catalytic amination of alcohols is a well-known process. By this process alkylene oxides, hydroxyl-containing compounds, aldehydes, and ketones can be aminated by reacting the compounds with ammonia, primary amines or secondary amines in a continuous or batchwise process in the presence of hydrogen gas and a hydrogenation-dehydrogenation catalyst. All hydrogen atoms on an ammonium or amine nitrogen are potentially replaceable by the alkyl radical of the alkylene oxide, hydroxyl-containing compound, aldehyde and ketone, so that the reaction product will be a mixture of primary, secondary, and tertiary amines.
When aminating hydroxyl-containing compounds, such as ethylene glycols and ethanolamines, not only straight-chain di- and polyamines, but also branched chain polyamines and six-membered heterocyclic amines, such as piperazine, morpholine, and their derivates, are obtained. The most desirable products in the manufacture of ethylene amines are those containing mainly primary amino groups. Ethylene amines containing tertiary amino groups and heterocyclic rings are of less commercial interest.
Various catalysts have been used to catalyze the process and most of them are based on nickel and/or cobalt. In order to improve the selectivity in respect to the product mix and to increase the reaction rate, a large number of promotors have been used, such as compounds of copper, magnesium, chromium, iron, and zinc. Patents describing amination of organic substances include U.S. Pat. No. 1,449,423 to Lowy et al and U.S. Pat. No. 2,365,721 to Olin et al.
U.S. Pat. No. 3,766,184 to Johansson et al discloses a nickel and/or cobalt and iron-containing catalyst which increases the formation of ethylene diamine and decreases the formation of piperazine. In U.S. Pat. No. 3,278,598 to Markiewitz, a Raney nickel catalyst is described in which rodium, palladium, or ruthenium supported on carbon is introduced as a co-catalyst. However, this catalyst increases the formation of secondary amines at the expense of primary amines.
U.S. Pat. No. 4,115,463 to Murtha discloses a catalyst for conversion of aromatic hydrocarbons to cycloalkylaromatic hydrocarbons. The catalyst consists essentially of from 0.01 to 0.3 wt % ruthenium, from 0.03 to 1.0 wt % nickel, and a support material. The catalyst is prepared by a process in which ruthenium and nickel are applied to the support material, such as active clay or synthetic silica-alumina, as alcoholic or aqueous solutions of a ruthenium halide salt and a nickel halide salt. Following impregnation, the catalytic composite is dried under conditions sufficient to remove solvent, but insufficient to calcine the catalyst composition. In the conversion, monocyclic aromatic hydrocarbons are contacted by the catalyst in the presence of hydrogen at a temperature ranging from 100.degree. to 275.degree. C. Prior to contacting the feedstock, the catalyst may be treated by flowing hydrogen over the catalyst for 0.1 to 10 hours at 100.degree. to 275.degree. C. In the finished catalyst, however, the nickel continues to be present as the nickel halide salt
In U.S. Pat. No. 4,510,320 to Pesa et al, a catalyst is disclosed for producing aliphatic carboxylic esters from acetic acid and synthesis gas. The catalyst contains mixed oxides of ruthenium, nickel, an alkali metal selected from Na, Li, K, Rb and Cs, and optionally a promotor metal oxide selected from Co, Cd, Zn, or mixtures thereof. The catalyst may be prepared by conventional methods including mixing components with a liquid, filtering, drying, calcining, such as for 3 hours at 350.degree. C. in air, and grinding, followed by coating upon a support, such as an alumina-silica support. Preferably the catalyst is utilized in a partially reduced state, for example, with hydrogen gas at 500.degree. C. for 2 hours, but the catalyst is not totally reduced to the metallic state and thus retains its oxide character.